Current conductor attachment for electric implements



Juiy 23, 1957 .1.1.. SCHNETTLER 2,800,636

' CURRENT CONDUCTOR ATTACHMENT ECR ELECTRIC INRLENENTS Filed Nov. 25, 1955 .IN In NAN @71957 CURRENT CONDUCTOR TTACHNENT'FOR ELECTRIC IMPLEMENTS;

Jerome; L, Sclmettlel',V Hales- Colfners, Wis., assigner to Milwaukee Electric Tool Corporatiom Milwaukeehwis., a corporation of Wisconsin Application November 25, 19553 S'erialNot 548,860

3 Claims. (Cl. 339-403) The present inventionl relates. generally to. improvements in electrically driven. devices, and, relatesV more specifically toimprovements inthe construction and mode of assembling and energizing current conductorsV of portable and universally movable electric implements.

TheV primary object ofV my invention is to provide an improved. constructionv for attaching the current conductors to. freely movable electrically driven` implements in. a manner whereby assembly of suchv devices is facilitated and the conductors are well protected,

In many types of portable electricallyv driven implements it is customary to` introduce the current conductors for driving the devices into the free ends ofthe manipulating handles or other parts, such asY the casings thereof through relatively sturdy but flexible insulating bushings clamped within but projecting outwardly away from these handles or casings. These bushings are ordinarily constructed ofV rubber-and; are formed integral with or vulcanized to rubber coverings for the portions of the conductors which extend outwardly away from the units, and. the free ends, of the several conductors usually project into these manipulating` handles. or casings and must be electrically connected1 to switches or other control mechanism normally concealed within the implements. In order to permit. application of these insulating and4 conductor protecting bushings tothe handles or casings of such electrical devices by clamping, it is necessary in most cases to split the enclosing structures` and to insert the bushings at the splits, and in many prior assemblages it was also diflicult to apply the bushings to the units in a man-ner whereby the conductors could be readily attached to the switches or other normally concealed electrical equipment.

It is therefore an important object of the present invention tol provide an improved conductor insulating and protecting bushing construction and attachment which avoids necessity of splitting the handles of such freely movable implements and which affords, a far better holding effect for such bushings without danger of short circuiting the conductors.

Another important object of this invention is to provide a simple but extremely durable and inexpensive insulated and flexible conductor insert bushing which enables the conductors to be quickly and effectively attached to the normally concealed electrical equipment of portable electrically energized appliances or the like.

A further important object of the invention is to provide an improved manipulating handle or casing assembly for electrically actuated portable implements such as electric tools, having a control switch mechanism partially or completely confined within the unit and in which the energizing current conductors can be readily applied to such mechanism and thereafter safeguarded against destruction.

Still another important object of my present invention 4is to provide a long lasting and neat appearing handle confined switch and electric current supply assemblage ICQ for universallymovableel'ectrtcally driven pistol grip tools orthe like which canY be properly installed or dismended by a. novice- These and other; more. Spe-.cie Objects and advantages. of the invention, will,` be apparent from the following detailedy description from, which it should be noted; that the gistf of the improvement is the provision of a current supply assemblage for portable. electrically driven implements comprising a specially constructed insulating and protective bushing for facilitating. attachment of the conductors to normally concealed electrical. equipment within the4 implement and for; thereafter guarding these condoctorsV against short-circuitingor other damage.

A clear conception of the features, constituting the present improvement, and of the construction and mode of assembling a typical,- electric tool unit embodying the invention,l may behadby, referring tothe drawing accompatiyirlgA and.v forming a part of this. Specification wherein like: referenceV characters. designate theA same or. similar partsv in the various views.

Eig. l is a, part sectional s ide View of an electric motor driven pcnitableV tool manipulating and actuating unit having a pistol grip handle and a vtrigger operated control switch, showingone of the improved current conductor insulating and protecting bushings in elevation finally attached to the handle, and the section having been taken centrally through, the unit handle along the line 1-1 Oilig- 2.;

Fig. 2 is a transverse section through the manipulating handle and conductor insulating bushing of Fig. l, taken along the line 2 2 but showing the bushing fastening special screws inA elevation; and

Eig.. 3 is a fragmentary section through the tool manipplating handle, similar to that of Fig. l, but showing the screws for normally holding the conductor insulating bushing in place, removedL and illustrating the manner in which this bushing may be shoved into the handle in order to facilitate attachment of the conductors to the control switch.

While the invention has been shown and described herein as having been appliedk to an electric motor driven portable and freely movable tool unit having a hollow pistol grip manipulating handle and a trigger actuated control switch confined within the handle, it is not intended to restrict the use of the improved features to such an implement; and it is also contemplated that specific descriptive terms be given the broadest possible interpretation consistent with the actual disclosure.

Referring to the drawing, the portable electric tool unit shown therein comprises in general, a hollow main casing 5 having a rotary electric motor confined within its medial portion 6 and being provided at one end with a removable reduction gear and power outlet housing 7 while its opposite end has a hollow pistol grip manipulating handle 8 formed integral therewith; a control switch 9 for the driving motor, confined within the upper portion of the handle S by means of a separate closure plate 10, and being operable by a trigger 11 to actuate the propelling motor; and an insulating and protecting bushing 12 for the motor energizing conductors 13, normally confined within the lower portion of the handle 8, but being projectable withinv the switch coniining cavity 14 of this handle during assembly of the unit.

The casing 5 and the housing 7 may be formed of light but durable metal such as aluminum, and the electric motor and its control switch are of well known construction and operation so that various kinds of tools driven by the unitV may be applied to work at any desired angle. The hollow pistol grip handle 8 which is formed integral with the casing 5, is provided with a cylindrical bore 16 at its lower end; and the conductor insulating bushing 12 which is formed of resilient rubber, is provided with an enlarged cylindrical upper portion 17 adapted to snugly fit but being insertible through the bore 16. Both the handle bore 16 and the periphery of the enlarged bushing portion 17 have a pair of parallel holes 18 intersecting their opposite sides, for snugly receiving the cylindrical Shanks of special bushing holding screws 19 having screw threads 20 coacting with internal threads formed in the handle 8 beyond the bore 16, and it is important that these coacting screw threads do not extend into the bushing portion 17 The lower end portion 21 of the resilient rubber bushing 12 which normally projects outwardly away from its enlarged cylindrical portion 17 is tapered and adapted to be flexed in any direction so as to eliminate short bending and possible breakage of the conductors 13; and these conductors 13 are insulation covered and are snugly confined within rubber coverings 22 vulcanized within the bushing 12, and extend some distance beyond the upper end of the bushing portion 17.

When the various parts of the electric tool actuating unit have been properly constructed as hereinabove described, the motor and speed reduction gearing may be assembled within the casing 5 upon removal of the front housing 7 in a well known manner, and with the handle closure plate 10 removed from the casing 5 the bushing 12 may be inserted through the handle bore 16 and upwardly through the hollow interior 14 of the handle 8 as illustrated in Fig. 3, sufficiently to permit the conductors 13 to be easily and firmly attached to the switch 9. After such attachment of the conductors 13 has been effected, the bushing 12 may be retracted until its enlarged cylindrical portion 17 becomes snugly confined within the cylindrical bore 16 at the lower end of the handle 8 as in Fig. 1, whereupon the two special screws 19 may be applied within the holes 18 and to the screw threads 20 in the manner illustrated in Fig. 2. The control switch 9 and actuating trigger 11 may thereafter be installed within the handle 8 after which the closure plate 10 may be fastened in place so as to complete the assemblage. The portable implement may thereafter be manipulated and moved freely in any direction in a well known manner without danger of breaking the conductors 13 or otherwise undesirably interrupting or short circuiting the current supply. The implement may also be pulled by or dangled from its conductor confining cord 22 without danger of having the bushing 12 pulled from within the bore 16 or having the conductors 13 torn apart.

From the foregoing detailed description of the construction and mode of assembling, it should be apparent that the present invention in fact provides a current conductor attachment for electrically driven implements of various types, which may be conveniently assembled and which insures long life for the completed unit. The improved formation of the conductor insulation bushing 12 with its enlarged retaining portion 17 snugly fitting an opening such as the bore 16 and provided with opposite side notches adapted to coact with the cylindrical Shanks of the screws 19, not only facilitates assembly, but also firmly holds the bushing 12 in proper position against possible axial shifting, and it is noteworthy that the crosssection of the opening 16 and bushing enlargement 17 need not be circular. The special formation of the screws 19 with only cylindrical portions devoid of screw threads but snugly fitting the holes 18 and coacting with the opposite side notches of the bushing portion 17 positively prevents cutting of the bushing 12 at these notches. The lower end of the handle 8 or other part of the implement enclosure within which the bushing 12 is confined, need not be split as in the past, but provides a solid continuous ring snugly embracing the enlarged portion 17 of the bushing 12 and when this bushing portion has beenlocked in place by the screws 19 as in Figs. 1 and 2 it willobviously require a tremendous pull on the cord l22 0r @Klen- ,4 sion 21 in order to Withdraw the bushing 12 axially from within the implement enclosure.

However, when the screws 19 have been removed, as in Fig. 3, the bushing 12 may be injected through the bore 16 and hollow interior 14 as far as desired in order to permit convenient attachment of the conductors 13 to the control switch 9, and this feature makes it unnecessary to provide long extensions of these conductors beyond the enlargement of the bushing 12, and also eliminates excessive conductor stock within the handle which might otherwise interfere with the movement of the trigger 11. The conductors 13 are also compactly confined within the resilient insulating bushing 12 and are amply protected against possible shifting and breakage due to short bending by the flexible tapered portion 21 of the bushing which also presents a neat and highly finished appearance. The improved current conductor attachment may be applied to any other enclosing part of an electrically energized implement, and the improved structure can be produced at low cost and has proven highly satisfactory and successful in actual use.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of assembling the portable electric tool unit herein specifically shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

I claim:

1. In a current conducting assemblage for electrical implements, a casing forming an enclosure for electrical l apparatus and having a' continuous integral ring portion provided with a bore connecting the casing interior with its exterior for the introduction of current conductors to the apparatus housed within the casing, an elongated conductor confining and insulating bushing having a circular portion insertible axially within said bore from the casing exterior and adapted to snugly fit the bore and also having a flexible tubular portion extending outwardly of the casing for also confining and for protecting the conductors against short bends adjacent to said casing bore, said integral ring portion having a transverse hole therein and said circular bushing portion having a transverse local side notch in its periphery alineable with said hole, and a retainer pin for said bushing detachably confined within said casing hole and being cooperable with said bushing notch to prevent both axial displacement and rotation of the bushing relative to said bore.

2. In a current conducting assemblage for electrical implements, a casing forming an enclosure for electrical apparatus and having a continuous integral ring portion provided with a bore connecting the casing interior with its exterior for the introduction of current conductors to the apparatus housed within the casing, an elongated conductor confining and insulating bushing having a circular portion insertible axially within said bore from the casing exterior and adapted to snugly fit the bore and also having a flexible tubular portion extending outwardly of the casing for also confining and for protecting the conductors against short bends adjacent to said casing bore, said integral ring portion having spaced transverse holes therein and said circular bushing portion having transverse opposite side notches in its periphery alineable with said holes, and a retainer pin for said bushing detachably confined within each of said casing holes and being cooperable with the adjacent bushing notches to prevent both axial displacement and rotation of the bushing relative to said bore.

3. In a current conducting assemblage for electrical implements, a casing forming an enclosure for electrical apparatus and having a continuous integral ring portion provided with a passage connecting the casing interior wtih its exterior for the introduction of current conductors to the apparatus housed within the casing, an elongated conductor confining and insulating bushing having an end portion insertible axially within said passage from the casing exterior and adapted to snugly fit the passage and also having a flexible tubular portionV extending outwardly of the casing for also confining and for protecting the conductors against short bends adjacent to said casing ring portion, said integral ring portion having a transverse hole therein and said end bushing portion having a transverse local side notch in its periphery alineable with said hole, and a retainer pin for said bushing detachably conned within said casing hole and being cooperable with said bushing notch to prevent both axial displacement and rotation of the bushing relative to said bore.

References Cited in the le of this patent UNITED STATES PATENTS 1,977,224 Albertson oct. 16, 1934 

